Telegraph system



y 0, 1938. J. o. CARR ET AL 2,116,506

TELEGRAPH SYSTEM Filed Feb. 16, 1955 INV EN TOR. JOHN O. CARP A TTORNE Y.

4405/??- H. RE/GEP Patented May 10, 1938 UNITED STATES PATENT OFFICE ""auam mama srs'rau mm o. Carr, Park Ridge, and-Albert n. miner;

n, lll., assignors to Teletype Corporation, Chicago, 111., a corporation oi Delaware Application February 16, 1935, Serial No. 6,830

20 Claims. (CI. 17H) tical operating speeds are attainable, which,

makes it advisable to provide equipment whereby the output of two or more keyboard operators may be transmitted over a single communication channel to insure that the channel will be operated at its maximum e-ificiency.

Accordingly, the principal object of the present invention is provision 01 a telegraph system involving a single signalling channel and a plurality of transmitters arranged for eflicient operation of the signalling channel at its maximum capacity by automatically associating the transmitters with the signalling channel alternately or in a selected sequence.

A feature of the invention is the provision of. a telegraph system having a single signalling circuit with a switching mechanism responsive to a local signalling condition established by an operator for automatically and alternately or in predetermined sequence connecting with the signalling circuit a plurality of transmitters operated by a control form.

The above and other objects of the present invention are achieved by providing a single signalling channel. extending from a transmitting point where there is located a plurality of separate and distinct transmitting units, each including individual tape transmitters and start-stop distributors. The tape transmitters, as is common practice in telegraph operation, are controlled by a control tape carrying perforations indicative of a message to be transmitted, and the transmitters according to this invention are controlled further by a switching control perforation prepared by the operator assigned to each unit for determining the moment of switching one transmitter from the channel and connecting another transmitter thereto. Switching of the transmitters is effected through a changeover relay for each transmitter and through circuits interconnecting the changeover relays. The

changeover relays respond to an added control circuits are completed when the previously eflec-' tive transmitter has completed its cycle of operation incident the transmission of the character represented by the code perforations in the tape adjacent the added control'perioration, thus in suring complete transmission of the last character of the message being transmitted irom the then eifective transmitter.

The invention also embodies mechanism for disabling any transmitting unit or units.

The invention will be more fully understood from the following description, taken in connection with the accompanying drawing in which Fig. 1 illustrates diagrammatically a system involving two transmitting units to be connected alternately and automatically to a single telegraph transmission channel, and Fig. 2illustrates a section of controlling tape.

Apparatus at the transmitting station com prises two transmitting units 6 and 1 which are shown with transmitting unit 6 operatively con-, nected to line conductor I. Unit 6 comprises an automatic tape-controlled transmitter Ii associated with a transmitting distributor l2 of startstop type whose operating or non-operating condition is controlled by stop cam I3 and start magnet I. There is provided in connection with the transmitter II a sixth contact element It which responds to a changeover perforation in row C, Fig. 2, or in an ultra-coda] position in the controlling tape as prepared by a keyboard perforator, there being code perforationsarranged in five rows to present characters of messages to be transmitted.

Transmitting unit 8 is associated with its companion transmitting unit I through a series circuit to line conductor 8 and also by symmetrical circuits which interconnect two control relays ll and i8 and two timing contacts l9 and 20. An energizing circuit for magnet ll extends from battery through winding of magnet ll, top contact of relay II, timing cam follower 22, contact 20, and resistor 23 to ground. A companion circuit extends from battery through winding of magnet 24, top contact of relay l8, timing cam follower 25, contact l9, and resistor 26 to ground. Control relay ll, whose winding is connected at one terminal to battery, may be controlled by any one of four circuit branches to ground, through manual key 21 to ground for removing a unit from service, taut-tape switch 28 to ground, tapecontrol member l6 to ground, and holding contact 29 of control relay ll in series with middle contact of companion control relay l8 to ground. Corresponding circuits may be traced for the energization of relay l8 through manual switch messages.

30, taut-tape switch 3|, ultra-coda] contact 32 of tape transmitter 33, and through contacts of relays and I8.

As has been noted, each of the two units 6 and 1 is provided with an automatic tape-controlled transmitter II, and each such station has a keyboard perforator of any known construction for forming in a tape a series of code perforations representing the message and controlling the transmitter II, but modified by addition of a special key for perforating an added ultra-codal record or perforation in row C, Fig. 2, to control contact elements I6 and 32.

Operation of the described transmission units is as follows:

- Beginning operation The condition of awaiting beginning of transnected, with manual keys 21, 30 open, and with both taut-tape switches closed and relays II, I8 held energized by circuits through the taut-tape switches because the perforation of tape for transmission has not been begun.

At the beginning of operation, attendants at units 6 and I begin operating their keyboard perforators to provide slack tape and immediately thereafter one of the taut-tape switches 28, 3| opens its contacts. Assuming that switch 28 is first to open, it will interrupt an obvious closed circuit to deenergize relay H which will close the relay locking chain contact circuit at its middle relay contact, thus providing a holding circuit for the winding of relay I8 to be effective upon that relay after taut-tape switch 3i has been opened. By release and restoration of its armature, relay I'I will close its top back contact, where a circuit will be completed from battery through starting magnet I4, contact of relay I1, timing cam follower 22, its contact 20 and resistor 23 to ground, and this closed circuit by energization of starting magnet I4 and attraction of its armature will release the stop cam l3 and will permit rotation of distributor I2. Signals in accordance with the operation of transmitter I I as they appear in the perforated tape will be transmitted over line 8 through the rotation of distributor I2.

The condition of the apparatus of the structure after three-quarter revolution of shaft 42 is as shown in the drawing, with magnet I4 and relay I8 energized and with relay I1 deenergized and distributor l2 operating at unit 6.

Transferring transmission to another unit be transmitted so that .changeover from one unit to another unit shall occur between successive Instructions for changeover record in the tape therefore provide for the changeover perfoiation beingmade in association with the last code perforations of the last message which is being perforated for transmission before changeover. When at the operating unit the changeover record or perforation is sensed by the contact member IS, a changeover circuit is closed to be traced from battery through winding of magnet i1 and contact Hi to ground, energizing magnet I! to remove ground from its middle contact and open the holding circuit of relay I8, thus permitting relay [8 to deenergize and causing relay I8 to complete a holding circuit for relay E1 to be traced from battery through winding of relay II, contact 29 of relay II, and middle contact of relay I8, which holding circuit will become effective at the opening of contact I6. Top contact of energized relay I! will have opened the controlling circuit of starting magnet M; thus deenergizing that magnet to permit its armature to rest against the smooth edge of cam i3 through the remainder of the cycle of one code transmission. Later in the cycle of transmission and substantially at the end of the transmitting code cycle the contact member I6 is restored to its normal position shown, and timing cam follower 25 drops into a notch in timing cam 48, thus closing an energizing circuit for the starting magnet 24 at unit I to operate its armature 31 into its alternative position to release cam 45, permitting rotation of the brush arm of distributor M and permitting full operation of unit 1, pending closure of tape changeover contact 32.

It will be noted that the time required for transfer of line control from one transmitting unit to another transmitting unit will be very short when measured from the instant of stopping of shaft 82 to the instant of starting of shaft 43. When cam I3 engages armature 46, the notch of cam 48 is brought into registry with follower 25. Im mediately thereafter contact I9 is engaged by follower 25, closing the energizing circuit of starting magnet 24. There follows the magnetic lag of energization of magnet 24 and the mechanical delay in the operation of its armature, both of which time intervals are very short. The loss of line time on line 8 due to shift of control from unit to unit will be but a fraction of a code cycle for each changeover operation.

Removing a unit from service Should any operator desire to leave the -transmission set, the operation will be as follows: Assuming for illustration the operator at unit 6, then at the end of the last-message recorded in the tape a changeover signal is recorded and then blank tape and tape-feed perforations sufficient to permit the changeover signal toreach the transmitter feelers follow, after which, when distributor I2 has ceased operating, the switch 21 is closed. Transmission by distributor 44 continues until a recorded changeover signal reaches transmitter 33 and effects the operation of contact member 32 which energizes relay I8 whose holding circuit is open at middle contact of energized relay I I, and later upon return of contact member 32 to normal, permits deenergization of relay I8 for further operation of transmitter 44. After reopening switch 21, operation of transmitter I2 may be resumed.

Discontinuing transmission At the end of the transmission from both units, switches 21 and 30 may be closed, each after its associated transmitter ceases operating, or both tapes may be allowed to run taut to close switches 28 and 3|. I

Although the invention has been described in connection with a specific form thereof, it will be understood that it has further applications and is not intended to be limited in scope by the embodiment shown herein for illustration.

What is claimed is:

1. In a telegraph system, a plurality of trans- 75 mitters, changeover relays for conditioning said transmitters one by one to transmit eiiective printi g code combinations oi signals, a circuit, and m ans controlled by one of said transmitters while transmitting an effective printing code for closing said circuit to control said changeover relays to decondition the said one of said transmitters and to condition another of said transmitters for operation.

2. In a telegraph system, a transmission line, a plurality of transmitters, means for conditioning individually one or said transmitters to transmit printing code combinations oi signals to said line and rendering the other of said transmitters ineffective, and means operable by an operating one of said transmitters while transmitting an eiiective telegraphic code for controlling said means to decondition the said operating one of said transmitters and to condition another of said transmitters for operation.

3. In a telegraph system, a plurality of transmitters, means for conditioning said transmitters successively to transmit effective printing code combinations of signals, further means eii'ective by one of said transmitters while transmittingan eh'ective printing code for controlling said means to decondition the said one or said transmitters said transmitters while transmitting a printing code to said line which operates said control means to change the control of said line from one to another ofsaid transmitters.

5. In a telegraph system, a line, a plurality of printing code transmitters associated with said line for transmission of printing code signals thereover, switching means responsive to a local signal generated by one of said transmitters while transmitting a printing code to said line. and means eiiective for changing said switching means between successive eilective printing codes from one to another of said transmitters subsequently to stopping one 01 said transmitters and in a time period less than the transmission period of one printing code.

6. In a telegraph system, a line circuit, a plurality oi tape controlled code transmitting devices, means for conditioning said transmitting devices oneat a time, a local circuit extending from a conditioned transmitter to said means, and means for applying an impulse to said circuit to operate said means to decondition said conditioned transmitter controlledby an ultracodal perforation.

7. In a telegraph system, a line circuit, a plurality of code transmitters for transmitting printing codes of impulses over said line circuit from one transmitter at a time, and means for transferring operation from one of said transmitters to another comprising a local circuit, and means under direct control of an ultra-codal perforation in a tape for rendering said local circuit effective to discontinue transmission tosaid line circuit from one of said transmitters and commence transmission to said line circuit from another of said transmitters. i

8. In a telegraph system, a line circuit, a plurality of code transmitters for transmitting printing codes of impulses over said line circuit from one transmitter at a time, means for transferring operation from one or said transmitters'to another, and means under control of an ultra-coda! perforation sensed concurrently with printing code perforations in a tape for controlling said means.

9. In a telegraph system, a line circuit, a plurality oi transmitters for transmitting printing codes 01' impulses over said line circuit from one transmitter at'a time, means controlled by an ultra-codal perforation in a tape, and means controlled by said means concurrently with the transmission over said line circuit of a printing code of impulses for transferring the control of said line circuit from the then operating transmitter to another transmitter.

10. In a telegraph system, a transmission circuit, a plurality of transmitters for the transmission of code signals over said circuit in response to signals sensed in a control form, means operated concurrently with the transmission 01' a code signal for preparing conditions for changeover to another transmitter in response to a further signal concurrently sensed in the control form and means eflective for thereafter completing the change-over.

11. In a telegraph system, a plurality of transmitters having'means for producing a uniform code-cycle transmission period, a transmission line common to said transmitters, transmittercontrolling circuits,.contact meansresponsive to a transmitter and operating to close a transmitter-controlling circuit after a transmitter has reached its stop position, and starting means in another transmitter responsive to said transmitter-controlling circuit and operating to start said other transmitter in a time interval shorter than one code-cycle transmission period.

12. In a telegraph system, a transmission circuit, a plurality of transmitters arranged to transmit code signals to said circuit selectively from a control form, means for preparing conditions local to said transmitters for effecting a changeover under control of a signal in the control form while transmitting to the circuit a code signal, and means under the control of said means for changing the connections from one transmitter to another transmitter in a time period less than the time period of transmission of a code signal.

13. In a telegraph system, a transmission circuit, a plurality of transmitters including a 1'0- tary distributor and a record reader responsive to conditions in a control form. means for rendering said transmitters operatively effective with said circuit, and means responsive to a condition in said control form accompanying intelligence characters therein for stopping the rotary distributor of one transmitter and starting the rotary distributor of theother transmitter after the impulses indicative of the intelligence character have been transmitted.

it. In a telegraph system, a transmission circuit, a plurality of transmitters, means respo'nsive to a signal accompanying a group of intelligence signals andeflective simultaneously therewith, and means operated from said means to control the establishment of conditions to'render a transmitter ineffective with said circuit and render another transmitter operative with said circuit.

15. In a telegraph system, a transmission circuit, a. plurality of transmitters, means responsive to a signal accompanying a group of intelligence signals and effective simultaneously therewith,

, establishment of conditions to render a transmitter ineil'ective with said circuit and render another transmitter operative with said circuit, and means operative after the intelligence signals have been transmitted to complete the established conditions.

16. In a telegraph system, a transmission line, a plurality of transmitters arranged to beefiective for the transmission of intelligence telegraphically to said line, means for generating an electric impulse while transmitting code signals to said line from a transmitter, means controlled by said electric impulse to prepare for rendering the then operative transmitterineflective and another transmitter efiective, and means efi'ective after the transmission of the code signal for completing the prepared conditions and starting transmission from the other transmitter.

17. In a telegraph system, a transmission line, a plurality of transmitters arranged to be effective for the transmission of intelligence telegraphically to said line, means for generating an electric impulse simultaneously with the transmission of a code signal of intelligence, relay means operated by said impulse to establish conditions preparatory to rendering the then operating transmitter ineffective and another transmitter eflective, and means effective after the transmission 01 the code signal for completing the conditions and starting transmission from the other transmitter.

18. In a telegraph system, a line, a plurality of printing code transmitters common to-said line, means in each transmitter for generating a local signal directly in response to a perforation in a tape while printing code signals are being transmitted to said line, and change-over control means responsive to said local signal for changing the control of said line from one to another of said transmitters. I

19. In a telegraph system, a transmission circuit, a plurality of transmitters, means to control the establishment of conditions to render a transmitter ineflective with said circuit and render another transmitter operative with said circuit, additional means to cause said first means to be responsive to a signal accompanying a group of intelligence signals and eflective simul taneously therewith, and means effective after the intelligence signals have been transmitted to complete the established conditions.

20. In a telegraph system, a plurality of transmitters, a transmission line common to said transmitters, switching means controlled by each transmitter when in its stopped condition, and means controlling the operation of said transmitters operated in response to the operation of said switching means for releasing its transmitter subsequent to the stopping of the other transmitter.

JOHN O. CARR. ALBERT H. REIBER. 

